81st Field Artillery Regiment is a reserve unit of Philippine Commonwealth Army activated in August 1941 as part of 81st Infantry Division.

However, no artillery guns reached Visayas and Mindanao as SS Corregidor sunk at Manila Bay.

Major John P. Woodridge was the senior instructor but assumed command in January 1942.

Lieutenant Colonel Woodridge transferred to Mindanao via Bugo port in Cagayan de Oro, Misamis Oriental.

[citation needed] Kawamura Detachment appeared in Macajalar Bay and started landing in Bugo and Tagaloan beach.